Oversized Air Compressor

[Gaunt596]

How often are you seating rally car tires??

not every day, but when i do its 12-14 tires at a time.

Yes. Cost of ownership is huge with an air compressor. If you use 50hp once a month and every other time you use 7.5hp, why would you buy a 50hp?

so,for reference, i paid all of $200 for this thing. even if it blows up after a year, im still winning on price. id love for it to last longer than that, but if it dosent then so be it. all i truly care about is not cooking the motor, since im in full price on that.

Who is talking about 50hp?

If the guy needs and wants 175psi,let him go for it.

I think it is silly to spin a 7.5hp motor to run small tools like an impact and a sander, but to each his own

theres more than that in the picture, blast cabinet, HVLP spray guns, tire changer that needs air, potentially a portable soda blaster for bigger jobs here soon, and who knows what else ill buy in the future.

Me too. Seems like a waste to have a two stage compressor cut out at 125.

my thoughts exactly. plus once i thought about it do do have some pretty air hungry tools that could use the extra reserve in the tank from more pressure and flow from the bigger HP option.

 

[sberry]

5 hp is a benchmark for real work for a man, 7.5 can run 2 so to speak and really helps with sandblast if that's a concern
I use a 3 as my master, I got big yanks and really gotta work to outrun it especially if I adjust the tool. Milder starts and longer run don't bother me but faster charge and steady sanding make 5 easier to run with less discipline. 7.5 is for those truly air dependant.

 

[sberry]

Ain't no point in slamming on resedential air unless you got to. I am on a long rural circuit, got a small ******, smaller motor is ok.

 

[ekimneirbo]

My understanding is that you may be able to use the 3 phase starter that came with your compressor and save the cost and hassle of replacing it. They aren't cheap. Supposedly if you disconnect what would be the extra 3 phase wire inside, it operates just like a single phase starter. Don't remember where I saw this, but I had already purchased a single phase for mine before I saw it.

I don't know why anyone would bother to call their power company before they hook up a compressor or any large tool. Your service from the power company is either 200 amp or its some old outdated service that needs to be upgraded to 200 if you have any power tools. Once they supply the 200 amps, its none of their business how you use it.

 

[u3b3rg33k]

My understanding is that you may be able to use the 3 phase starter that came with your compressor and save the cost and hassle of replacing it. They aren't cheap. Supposedly if you disconnect what would be the extra 3 phase wire inside, it operates just like a single phase starter. Don't remember where I saw this, but I had already purchased a single phase for mine before I saw it.

I don't know why anyone would bother to call their power company before they hook up a compressor or any large tool. Your service from the power company is either 200 amp or its some old outdated service that needs to be upgraded to 200 if you have any power tools. Once they supply the 200 amps, its none of their business how you use it.

I think if you read their rules you'll find that's not the case.

if you're in a residential area, you are likely sharing a transformer with multiple houses, and if they get enough complaints from their other customers, they'll eventually come knocking if it's something you're doing.

 

[mike93lx]

I don't know why anyone would bother to call their power company before they hook up a compressor or any large tool. Your service from the power company is either 200 amp or its some old outdated service that needs to be upgraded to 200 if you have any power tools. Once they supply the 200 amps, its none of their business how you use it.

Not true at all, besides very large motors can exceed 200a at startup.

You may want all that to be true, but that doesn't make it so

 

[redmondjp]

My understanding is that you may be able to use the 3 phase starter that came with your compressor and save the cost and hassle of replacing it. They aren't cheap. Supposedly if you disconnect what would be the extra 3 phase wire inside, it operates just like a single phase starter. Don't remember where I saw this, but I had already purchased a single phase for mine before I saw it.

The starter, so long as it is rated for the amps/HP, can also be used for a single-phase motor. Just did this conversion on a 3phase 5HP Speedaire (Champion) compressor for my brother. Had to order new bimetallic heater strips for the overload to match the single-phase motor. Contactor coil runs 208-230V nominal so it also works on 240V single phase (was wired for 208V 3ph originally) as a control voltage. You use two of the three poles on the starter/contactor.

 

[metalmagpie]

Ok, so it's not quite an R30, since it has reed valve heads by the look of it, but I'd be surprised if the bore and stroke are different. It's definitely something Champion built, probably an earlier cheaper line for Grainger to sell as a Speedaire or Dayton. I'd do some measuring of the pulleys and calculate the current running rpm with the motor it has to see if it works out to be the same as the rpm specs for the R30. I'm confident there is little difference, but I wouldn't want to send you off with incorrect info. It should be a very good unit for you if it is in good shape.

It's from Champion's RV series. Probably "reciprocating vane"? Vane meaning vane-type reed valves? There was an RV-30, that might be it.

 

[redmondjp]

It's from Champion's RV series. Probably "reciprocating vane"? Vane meaning vane-type reed valves? There was an RV-30, that might be it.

I think the 'V' stands for value. It was a reduced-cost (reed-valve head, less cooling fins on the cylinder, etc.) design. I bought one of these a few years ago that was Speedaire (Grainger house brand) and listed that way - it would have sold for more if it was listed as a Champion IMO . . .

 

[no704]

Just do a LS swap on it!

 

[dnschmidt]

The OP said that "I bought too big of an air compressor." THERE IS NO SUCH THING!

 

[GeoBruin]

Necro thread FYI.

 

[Walkers]

a 10hp phase converter drive can be had for $1200. no need to spend 3x that.

An RPC on a compressor *****!

 

[NFH2740]

Nmv

 

[u3b3rg33k]

An RPC on a compressor *****!

I'm talking about a VFD. you can even use the internal logic to run a 24V solenoid as an unloader. something like: contact ON until running speed achieved. supported by even basic VFDs. just need a check-valve and a solenoid to unload the head/vent to atmo behind a checkvalve.

 

[Walkers]

I'm talking about a VFD. you can even use the internal logic to run a 24V solenoid as an unloader. something like: contact ON until running speed achieved. supported by even basic VFDs. just need a check-valve and a solenoid to unload the head/vent to atmo behind a checkvalve.

You said phase converter. THe cost of a vfd to run this cheap 3 phase compressor would pay for a new single phase compressor, maybe even 3 of them.

 

[u3b3rg33k]

You said phase converter. THe cost of a vfd to run this cheap 3 phase compressor would pay for a new single phase compressor, maybe even 3 of them.

phase converter DRIVE. I even included the price. I said nothing about an RPC.

 

[Walkers]

phase converter DRIVE. I even included the price. I said nothing about an RPC.

Gotcha, I missed the word drive. Usually an RPC and phase converter are synonymous , and a VFD is usually referred to as, well, a VFD. Still an poor option for a compressor, where a single phase motor works it fine for a few hundred bucks.

 

[seber]

Just look for any 7 1/2 hp motor. Don't worry about frame size as long as it is base mounted. You can remount any motor base on the flat mounting plate. Just drill holes as needed.

 

[u3b3rg33k]

Gotcha, I missed the word drive. Usually an RPC and phase converter are synonymous , and a VFD is usually referred to as, well, a VFD. Still an poor option for a compressor, where a single phase motor works it fine for a few hundred bucks.

it depends on what you're trying to do, but yeah. some applications it makes sense, like running motors bigger than the poco wants you to (say, where you can support FLA but not LRA), if you're doing any kind of load following with PI/D or energy savings (paying to pump and hold at 90/125 PSI is cheaper than ping-ponging off of 150-175PSI, etc.

I'm also a big fan of being able to use VFDs as smart motor starters. they're often better at protecting a motor (if properly configured) for the money, and trip history is not something electro-mechanical protection offers.